Find out why your AI agent forgot.

Your agent told a customer they're vegan -- then recommended a steak restaurant. Your support bot asked for the account ID the customer already gave. Your personal assistant lost the project deadline mentioned three messages ago.

These are memory failures. They happen in production every day. And until now, there was no way to test for them before they reach your users.

memeval detects memory corruption, measures retrieval quality, and catches context loss in multi-turn conversations -- across any memory provider.

pip install memoryeval
memeval run --adapter in_memory

Session: Mid-Conversation Correction
  [turn 1] User: "Book a flight to Tokyo"
  [turn 3] User: "Actually, change that to Seoul"
  [assert] Query: "Where does the user want to fly?"
  [result] Retrieved: "Seoul"  -- PASS

Preference Update
  [setup]  Stored: "User is vegetarian"
  [step 1] Stored: "User switched to vegan"
  [assert] Query: "dietary preferences"
  [result] Retrieved: "vegetarian" AND "vegan"  -- FAIL: old fact not replaced

What it catches

Contradiction retention -- your memory stores "User earns $80K" and "User earns $120K" side by side. memeval detects this using embedding similarity analysis, not keyword matching.

Context loss in conversations -- a fact shared in turn 1 disappears by turn 10. memeval tests recall depth across 10+ turn conversations.

Stale data -- user corrected a preference but the old value still appears in search results. memeval verifies that updates propagate.

Cross-user data leakage -- user A's private data shows up in user B's session. memeval plants sentinel values and probes for leaks.

Silent forgetting -- deleted facts are gone, but so are facts that should have survived. memeval measures both forgetting precision and retention rate.

Quick start

pip install memoryeval

# Run 30 built-in scenarios against the test adapter
memeval run --adapter in_memory

# Test against real Mem0 (requires OPENAI_API_KEY)
pip install memoryeval[mem0]
memeval run --adapter mem0

# Compare providers side-by-side
memeval benchmark --adapters in_memory --adapters mem0

Multi-turn conversation testing

memeval tests what users actually care about -- does the agent remember what was said earlier in this conversation?

name: "Customer Support Multi-Turn"
steps:
  - create_session:
      session_id: "ticket_789"

  - add_message:
      session_id: "ticket_789"
      role: "user"
      content: "I was charged $99 but my plan is Basic at $29"

  - add_message:
      session_id: "ticket_789"
      role: "user"
      content: "My account email is frank@email.com"

  - add_message:
      session_id: "ticket_789"
      role: "user"
      content: "Please refund the difference"

  # 3 turns later, does the agent still know the issue?
  - assert_context:
      session_id: "ticket_789"
      query: "What is the billing issue?"
      expected_contains: ["99"]

Each adapter maps sessions to the provider's native concept:

• Mem0: run_id
• Zep: threads
• Letta: agent message sequence

30 built-in scenarios

Category	Scenarios	What they test
Session (6)	Basic recall, correction, 10-turn depth, isolation, support, preferences	Multi-turn conversation memory
Core (7)	Basic recall, adversarial, multi-hop, entity resolution, negation, high-volume, scale	Fact storage and retrieval
Lifecycle (6)	Preference update, contradiction, rapid updates, stale data, forgetting, GDPR deletion	Memory evolution over time
Governance (3)	Privacy isolation, multi-user isolation, cross-session recall	Data boundaries
Edge cases (2)	UTF-8 characters, empty/boundary conditions	Robustness
Operations (6)	Cascading deletion, consolidation, support handoff, context restoration, soft contradictions, scale stress	Memory management

What it measures

7 evaluation dimensions, each with concrete metrics:

Dimension	What it catches	How
Recall	"Agent forgot what I said"	Store facts, search for them, measure hit rate
Relevance	"Agent returned the wrong memory"	MRR and NDCG@k on ranked results
Consistency	"Agent has contradictory facts"	Embedding similarity to detect same-topic divergence
Update propagation	"Old value still appears after correction"	Update fact, verify old value is gone
Forgetting quality	"Deleted the wrong things"	Selective deletion precision + retention rate
Latency	"Memory operations are too slow"	p50/p95/p99 for reads vs writes separately
Privacy	"User A's data leaked to User B"	Sentinel-based cross-session probing

Use in CI/CD

# JSON reports for pipeline integration
memeval run --adapter mem0 --output report.json

# Reproducible multi-run benchmarks
python scripts/run_benchmark.py --adapter mem0 --runs 3 --output results/

# .github/workflows/memeval.yml
- name: Memory evaluation
  run: memeval run --adapter mem0 --output report.json
  env:
    OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}

Use with pytest

pytest --memeval-adapter=mem0

memeval auto-discovers YAML scenario files. Write your own or use the 30 built-in ones.

Use in Python

import asyncio
from memeval import evaluate, InMemoryAdapter

async def main():
    adapter = InMemoryAdapter()
    results = await evaluate(adapter=adapter, scenarios="builtin")

    for r in results:
        status = "PASS" if r.passed else "FAIL"
        print(f"[{status}] {r.scenario.name}")

asyncio.run(main())

Supported providers

Provider	Session model	Install
In-Memory (testing)	dict-based	Built-in
Mem0	run_id	pip install memoryeval[mem0]
Zep	threads	pip install memoryeval[zep]
Letta	agent state	pip install memoryeval[letta]
Custom	You define it	See writing adapters

Benchmark findings

Single-run results from 2026-05-27 (memeval 0.1.2, Python 3.14, macOS ARM64, Mem0 self-hosted with gpt-4o-mini). Not statistically significant -- see methodology for reproducible multi-run benchmarks.

Finding	Detail
Mem0 recall: 1.000	LLM fact extraction makes semantic retrieval excellent
Mem0 consistency: 0.917	Stores both old and new facts -- does not auto-resolve contradictions
Mem0 write latency: p95 ~3,500ms	Every write calls OpenAI for extraction
Mem0 search latency: p95 ~500ms	Retrieval is fast once facts are indexed
Zep graph: async indexing	Facts not searchable immediately after write

# Reproduce
python scripts/run_benchmark.py --adapter in_memory --adapter mem0 --output results/

Documentation

• Getting started
• Writing custom adapters
• Benchmark methodology

License

Apache 2.0